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Add subtree search, property filtering, and targeted DataContext inspection #69
Description
Report
A repeated WPF control set required one find_elements call followed by roughly 120 get_computed_properties calls. Selection state was visible through a binding and the computed Fill value, but find_elements could not use either value as a predicate.
The same investigation exposed two related limits:
get_data_contextserialized nested objects as type names instead of allowing selected nested fields.find_elementscould not restrict traversal to a known subtree.
Together these limits produced a noisy N+1 inspection workflow that was slow to cancel and hard to audit.
Requested behavior
Bounded property inspection
Allow an exact computed-property predicate in find_elements, or add a bounded batch operation.
{
"query": {
"type": "SelectableShape",
"computedProperty": {
"name": "Fill",
"equals": "#FFA8D7E5"
}
},
"maxResults": 10
}A batch alternative could accept a bounded set of element IDs and property names:
{
"elementIds": ["id-1", "id-2", "id-3"],
"propertyNames": ["Fill", "Points", "IsSelected"],
"maxElements": 120
}Targeted DataContext paths
Allow callers to request named paths without recursively serializing the full object graph:
{
"elementId": "...",
"propertyPaths": [
"CurrentSelection.Kind",
"CurrentSelection.Key"
]
}Subtree search
Let find_elements start from the same kind of root locator used by get_visual_tree:
{
"root": {
"automationId": "ITEMS_CANVAS"
},
"query": {
"type": "SelectableShape"
},
"maxResults": 10
}Safety and response requirements
- Keep element traversal, returned results, property predicates, property paths, and batch sizes bounded.
- Reject invalid or oversized requests before traversal.
- Report scanned and returned element counts.
- Report truncation and the limits applied to the request.
- Preserve cancellation throughout traversal and property evaluation.
- Do not turn DataContext inspection into an unrestricted recursive serializer.
Evaluation
Implementation approach and final scope still need verification against the current WPF agent and public tool contracts.
Activity
mkajander commentedon Aug 26, 2026
Implementation assessment:
root; the default compact profile drops it. The fix is to expose the existing bounded path in the compact schema.get_data_contextcan reuse the same limits for a one-shot projection without recursively serializing unrelated objects.The implementation will cap path count and depth, batch element count, properties per element, and total work. New agent fields and methods will be capability-gated so an older injected agent cannot silently ignore them.
mkajander commentedon Aug 26, 2026
Resolved in #70 and published as
v0.1.0-preview.28.Delivered:
find_elements.rootin the core profile for bounded subtree search.get_computed_properties_batchwith element and property limits, counts, truncation metadata, cancellation, capability checks, and stable public ID mapping.get_data_context.propertyPathsfor bounded dotted-path projections. Shared prefixes are read once per request.Computed-property predicates in
find_elementsremain deferred. They need a separate comparison contract for WPF-only routing, unset values, converters, brushes, and application-defined values. The batch operation resolves the reported N+1 call problem without guessing at those equality rules.CI passed all 784 tests. The release workflow built, tested, packed, and published the package, and NuGet now lists preview.28.